... :4.8 ,6.8,8.8,9.8..... DRYWALL SCREW,WOOD SCREW,CHIPBOARD SCREW. A good non-standard ... "A","AB", Threads for chipboard screw,wood screw,drywall screw;Type "M","UNC","UNF","BSW"threads for Machine ... is much deeper,it is convenient to tighten by screwdriver.3.As a credible manufacturer we are ,we can ... They are used in most of places such as drywall,concrete,chipboard,machine,wood...2) Main export market: ...